Better implementation for async loop control

lib/sandbox.js

@@ -275,16 +275,17 @@ function run(script, globals, timestamp, deviceData, extensionsCache, startRevis
   let extCache = sandbox.extensionsCache;
   let args = arguments;
 
-  let counter = 1;
+  let counter = 3;
   for (let key in sandbox.extensions) {
-    ++ counter;
+    counter += 2;
     extensions.run(sandbox.extensions[key], function(err, fault, res) {
-      if ((err || fault) && counter > 0) {
-        counter = 0;
-        return callback(err, fault);
+      if (err || fault) {
+        if (counter & 1)
+          callback(err, fault);
+        return counter = 0;
       }
       extCache[key] = res;
-      if (-- counter === 0)
+      if ((counter -= 2) === 1)
         if (status === 2)
           return run.apply(null, args);
         else
@@ -292,7 +293,7 @@ function run(script, globals, timestamp, deviceData, extensionsCache, startRevis
     });
   }
 
-  if (-- counter === 0)
+  if ((counter -= 2) === 1)
     if (status === 2)
       return run.apply(null, args);
     else